A wide variety of applications exist in commerce and industry wherein materials and products that are susceptible to corrosion may be protected from corrosive environments through the use of packaging or wrapping films. A common example of items in need of protection from corrosion involve materials and/or products manufactured from corrosion-susceptible metals, which tend to corrode through oxidation when exposed to oxygen in either a gaseous or liquid phase. As such, elements in the atmosphere such as gaseous oxygen and water vapor are agents that tend to cause corrosion in metal materials.
Various film forms have been developed and implemented as wrapping about such corrosion-susceptible materials. These films are often referred to as packaging films, as they are often times utilized in conjunction with product packaging applications. However, such films may also or instead be utilized in protective wrapping applications not commonly associated with product packaging. While films fabricated solely of polymeric materials assist in preventing corrosion agent access to the enclosed materials, certain films having further corrosion inhibiting characteristics have been developed and implemented.
Films currently utilized in corrosion inhibiting applications include those which contain vapor phase corrosion inhibitor (VCI) materials which vaporize from the film into the enclosed package to minimize corrosion caused by any moisture entering into or contained within the enclosure. Moreover, metallized films such as aluminum foil have been utilized as corrosion agent blocking layers to protect materials within the enclosure. Conventional corrosion inhibiting films are described in, for example, U.S. Pat. No. 4,944,916 issued to AT&T Bell Laboratories, and U.S. Pat. No. 5,209,869 issued to the same assignee as in the present application.
Certain manufacturers of protective packaging materials have further attempted to create a composite film structure by laminating a metal foil to a VCI-containing film. Such composite film structures, however, are typically expensive to prepare and are difficult to handle in production, since such composite structures must be prepared in a multi-step process.
Other films have been produced which utilize nano-clay particles dispersed in polyethylene or other polymeric materials. It has been reported that such films incorporating nano-clay particles exhibit improved barrier properties to oxygen and water, improved strength and flame-retardancy, as compared to conventional polyethylene films.
It is therefore a principal object of the present invention to provide a film for use in protecting packaged materials from corrosion, and which films contain both vapor phase corrosion inhibiting materials and nano-clay particles.
It is a further object of the present invention to provide a packaging film having both a corrosion agent inhibiting characteristic and a barrier protection characteristic, and which film is created through a single-step fabrication process.
It is a still further object of the present invention to provide a film formed through a single-step co-extrusion process that incorporates a vapor-phase corrosion inhibitor material and nano-clay particles therein.